videobuf-core.c

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/*
 * generic helper functions for handling video4linux capture buffers
 *
 * (c) 2007 Mauro Carvalho Chehab, <[e-mail]>
 *
 * Highly based on video-buf written originally by:
 * (c) 2001,02 Gerd Knorr <[e-mail]>
 * (c) 2006 Mauro Carvalho Chehab, <[e-mail]>
 * (c) 2006 Ted Walther and John Sokol
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>

#include <media/videobuf-core.h>

#define MAGIC_BUFFER 0x20070728
#define MAGIC_CHECK(is,should)	if (unlikely((is) != (should))) \
	{ printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }

static int debug = 0;
module_param(debug, int, 0644);

MODULE_DESCRIPTION("helper module to manage video4linux buffers");
MODULE_AUTHOR("Mauro Carvalho Chehab <[e-mail]>");
MODULE_LICENSE("GPL");

#define dprintk(level, fmt, arg...)	if (debug >= level) \
	printk(KERN_DEBUG "vbuf: " fmt , ## arg)

/* --------------------------------------------------------------------- */

#define CALL(q, f, arg...)						\
	( (q->int_ops->f)? q->int_ops->f(arg) : 0)

void* videobuf_alloc(struct videobuf_queue* q)
{
	struct videobuf_buffer *vb;

	BUG_ON (q->msize<sizeof(*vb));

	if (!q->int_ops || !q->int_ops->alloc) {
		printk(KERN_ERR "No specific ops defined!\n");
		BUG();
	}

	vb = q->int_ops->alloc(q->msize);

	if (NULL != vb) {
		init_waitqueue_head(&vb->done);
		vb->magic     = MAGIC_BUFFER;
	}

	return vb;
}

int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)
{
	int retval = 0;
	DECLARE_WAITQUEUE(wait, current);

	MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
	add_wait_queue(&vb->done, &wait);
	while (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED) {
		if (non_blocking) {
			retval = -EAGAIN;
			break;
		}
		set_current_state(intr  ? TASK_INTERRUPTIBLE
					: TASK_UNINTERRUPTIBLE);
		if (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED)
			schedule();
		set_current_state(TASK_RUNNING);
		if (intr && signal_pending(current)) {
			dprintk(1,"buffer waiton: -EINTR\n");
			retval = -EINTR;
			break;
		}
	}
	remove_wait_queue(&vb->done, &wait);
	return retval;
}

int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
		    struct v4l2_framebuffer *fbuf)
{
	MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	/* FIXME: This is required to avoid OOPS on some cases, since mmap_mapper()
	   method should be called before _iolock.
	   On some cases, the mmap_mapper() is called only after scheduling.

	   However, this way is just too dirty! Better to wait for some event.
	 */
	schedule_timeout(HZ);

	return CALL(q,iolock,q,vb,fbuf);
}

/* --------------------------------------------------------------------- */


void videobuf_queue_core_init(struct videobuf_queue* q,
			 struct videobuf_queue_ops *ops,
			 void *dev,
			 spinlock_t *irqlock,
			 enum v4l2_buf_type type,
			 enum v4l2_field field,
			 unsigned int msize,
			 void *priv,
			 struct videobuf_qtype_ops *int_ops)
{
	memset(q,0,sizeof(*q));
	q->irqlock   = irqlock;
	q->dev       = dev;
	q->type      = type;
	q->field     = field;
	q->msize     = msize;
	q->ops       = ops;
	q->priv_data = priv;
	q->int_ops   = int_ops;

	/* All buffer operations are mandatory */
	BUG_ON (!q->ops->buf_setup);
	BUG_ON (!q->ops->buf_prepare);
	BUG_ON (!q->ops->buf_queue);
	BUG_ON (!q->ops->buf_release);

	/* Having implementations for abstract methods are mandatory */
	BUG_ON (!q->int_ops);

	mutex_init(&q->lock);
	INIT_LIST_HEAD(&q->stream);
}

/* Locking: Only usage in bttv unsafe find way to remove */
int videobuf_queue_is_busy(struct videobuf_queue *q)
{
	int i;

	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	if (q->streaming) {
		dprintk(1,"busy: streaming active\n");
		return 1;
	}
	if (q->reading) {
		dprintk(1,"busy: pending read #1\n");
		return 1;
	}
	if (q->read_buf) {
		dprintk(1,"busy: pending read #2\n");
		return 1;
	}
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		if (q->bufs[i]->map) {
			dprintk(1,"busy: buffer #%d mapped\n",i);
			return 1;
		}
		if (q->bufs[i]->state == STATE_QUEUED) {
			dprintk(1,"busy: buffer #%d queued\n",i);
			return 1;
		}
		if (q->bufs[i]->state == STATE_ACTIVE) {
			dprintk(1,"busy: buffer #%d avtive\n",i);
			return 1;
		}
	}
	return 0;
}

/* Locking: Caller holds q->lock */
void videobuf_queue_cancel(struct videobuf_queue *q)
{
	unsigned long flags=0;
	int i;

	/* remove queued buffers from list */
	if (q->irqlock)
		spin_lock_irqsave(q->irqlock,flags);
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		if (q->bufs[i]->state == STATE_QUEUED) {
			list_del(&q->bufs[i]->queue);
			q->bufs[i]->state = STATE_ERROR;
		}
	}
	if (q->irqlock)
		spin_unlock_irqrestore(q->irqlock,flags);

	/* free all buffers + clear queue */
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		q->ops->buf_release(q,q->bufs[i]);
	}
	INIT_LIST_HEAD(&q->stream);
}

/* --------------------------------------------------------------------- */

/* Locking: Caller holds q->lock */
enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
{
	enum v4l2_field field = q->field;

	BUG_ON(V4L2_FIELD_ANY == field);

	if (V4L2_FIELD_ALTERNATE == field) {
		if (V4L2_FIELD_TOP == q->last) {
			field   = V4L2_FIELD_BOTTOM;
			q->last = V4L2_FIELD_BOTTOM;
		} else {
			field   = V4L2_FIELD_TOP;
			q->last = V4L2_FIELD_TOP;
		}
	}
	return field;
}

/* Locking: Caller holds q->lock */
static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
			    struct videobuf_buffer *vb, enum v4l2_buf_type type)
{
	MAGIC_CHECK(vb->magic,MAGIC_BUFFER);
	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	b->index    = vb->i;
	b->type     = type;

	b->memory   = vb->memory;
	switch (b->memory) {
	case V4L2_MEMORY_MMAP:
		b->m.offset  = vb->boff;
		b->length    = vb->bsize;
		break;
	case V4L2_MEMORY_USERPTR:
		b->m.userptr = vb->baddr;
		b->length    = vb->bsize;
		break;
	case V4L2_MEMORY_OVERLAY:
		b->m.offset  = vb->boff;
		break;
	}

	b->flags    = 0;
	if (vb->map)
		b->flags |= V4L2_BUF_FLAG_MAPPED;

	switch (vb->state) {
	case STATE_PREPARED:
	case STATE_QUEUED:
	case STATE_ACTIVE:
		b->flags |= V4L2_BUF_FLAG_QUEUED;
		break;
	case STATE_DONE:
	case STATE_ERROR:
		b->flags |= V4L2_BUF_FLAG_DONE;
		break;
	case STATE_NEEDS_INIT:
	case STATE_IDLE:
		/* nothing */
		break;
	}

	if (vb->input != UNSET) {
		b->flags |= V4L2_BUF_FLAG_INPUT;
		b->input  = vb->input;
	}

	b->field     = vb->field;
	b->timestamp = vb->ts;
	b->bytesused = vb->size;
	b->sequence  = vb->field_count >> 1;
}

/* Locking: Caller holds q->lock */
static int __videobuf_mmap_free(struct videobuf_queue *q)
{
	int i;
	int rc;

	if (!q)
		return 0;

	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	rc  = CALL(q,mmap_free,q);
	if (rc<0)
		return rc;

	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		q->ops->buf_release(q,q->bufs[i]);
		kfree(q->bufs[i]);
		q->bufs[i] = NULL;
	}

	return rc;
}

int videobuf_mmap_free(struct videobuf_queue *q)
{
	int ret;
	mutex_lock(&q->lock);
	ret = __videobuf_mmap_free(q);
	mutex_unlock(&q->lock);
	return ret;
}

/* Locking: Caller holds q->lock */
static int __videobuf_mmap_setup(struct videobuf_queue *q,
			unsigned int bcount, unsigned int bsize,
			enum v4l2_memory memory)
{
	unsigned int i;
	int err;

	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	err = __videobuf_mmap_free(q);
	if (0 != err)
		return err;

	/* Allocate and initialize buffers */
	for (i = 0; i < bcount; i++) {
		q->bufs[i] = videobuf_alloc(q);

		if (q->bufs[i] == NULL)
			break;

		q->bufs[i]->i      = i;
		q->bufs[i]->input  = UNSET;
		q->bufs[i]->memory = memory;
		q->bufs[i]->bsize  = bsize;
		switch (memory) {
		case V4L2_MEMORY_MMAP:
			q->bufs[i]->boff  = bsize * i;
			break;
		case V4L2_MEMORY_USERPTR:
		case V4L2_MEMORY_OVERLAY:
			/* nothing */
			break;
		}
	}

	if (!i)
		return -ENOMEM;

	dprintk(1,"mmap setup: %d buffers, %d bytes each\n",
		i, bsize);

	return i;
}

int videobuf_mmap_setup(struct videobuf_queue *q,
			unsigned int bcount, unsigned int bsize,
			enum v4l2_memory memory)
{
	int ret;
	mutex_lock(&q->lock);
	ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
	mutex_unlock(&q->lock);
	return ret;
}

int videobuf_reqbufs(struct videobuf_queue *q,
		 struct v4l2_requestbuffers *req)
{
	unsigned int size,count;
	int retval;

	if (req->count < 1) {
		dprintk(1,"reqbufs: count invalid (%d)\n",req->count);
		return -EINVAL;
	}

	if (req->memory != V4L2_MEMORY_MMAP     &&
	    req->memory != V4L2_MEMORY_USERPTR  &&
	    req->memory != V4L2_MEMORY_OVERLAY) {
		dprintk(1,"reqbufs: memory type invalid\n");
		return -EINVAL;
	}

	mutex_lock(&q->lock);
	if (req->type != q->type) {
		dprintk(1,"reqbufs: queue type invalid\n");
		retval = -EINVAL;
		goto done;
	}

	if (q->streaming) {
		dprintk(1,"reqbufs: streaming already exists\n");
		retval = -EBUSY;
		goto done;
	}
	if (!list_empty(&q->stream)) {
		dprintk(1,"reqbufs: stream running\n");
		retval = -EBUSY;
		goto done;
	}

	count = req->count;
	if (count > VIDEO_MAX_FRAME)
		count = VIDEO_MAX_FRAME;
	size = 0;
	q->ops->buf_setup(q,&count,&size);
	size = PAGE_ALIGN(size);
	dprintk(1,"reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
		count, size, (count*size)>>PAGE_SHIFT);

	retval = __videobuf_mmap_setup(q,count,size,req->memory);
	if (retval < 0) {
		dprintk(1,"reqbufs: mmap setup returned %d\n",retval);
		goto done;
	}

	req->count = retval;

 done:
	mutex_unlock(&q->lock);
	return retval;
}

int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
{
	int ret = -EINVAL;

	mutex_lock(&q->lock);
	if (unlikely(b->type != q->type)) {
		dprintk(1,"querybuf: Wrong type.\n");
		goto done;
	}
	if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
		dprintk(1,"querybuf: index out of range.\n");
		goto done;
	}
	if (unlikely(NULL == q->bufs[b->index])) {
		dprintk(1,"querybuf: buffer is null.\n");
		goto done;
	}

	videobuf_status(q,b,q->bufs[b->index],q->type);

	ret = 0;
done:
	mutex_unlock(&q->lock);
	return ret;
}

int videobuf_qbuf(struct videobuf_queue *q,
	      struct v4l2_buffer *b)
{
	struct videobuf_buffer *buf;
	enum v4l2_field field;
	unsigned long flags=0;
	int retval;

	MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);

	if (b->memory == V4L2_MEMORY_MMAP)
		down_read(&current->mm->mmap_sem);

	mutex_lock(&q->lock);
	retval = -EBUSY;
	if (q->reading) {
		dprintk(1,"qbuf: Reading running...\n");
		goto done;
	}
	retval = -EINVAL;
	if (b->type != q->type) {
		dprintk(1,"qbuf: Wrong type.\n");
		goto done;
	}
	if (b->index < 0 || b->index >= VIDEO_MAX_FRAME) {
		dprintk(1,"qbuf: index out of range.\n");
		goto done;
	}
	buf = q->bufs[b->index];
	if (NULL == buf) {
		dprintk(1,"qbuf: buffer is null.\n");
		goto done;
	}
	MAGIC_CHECK(buf->magic,MAGIC_BUFFER);
	if (buf->memory != b->memory) {
		dprintk(1,"qbuf: memory type is wrong.\n");
		goto done;
	}
	if (buf->state != STATE_NEEDS_INIT && buf->state != STATE_IDLE) {
		dprintk(1,"qbuf: buffer is already queued or active.\n");
		goto done;
	}

	if (b->flags & V4L2_BUF_FLAG_INPUT) {
		if (b->input >= q->inputs) {
			dprintk(1,"qbuf: wrong input.\n");
			goto done;
		}
		buf->input = b->input;
	} else {
		buf->input = UNSET;
	}

	switch (b->memory) {
	case V4L2_MEMORY_MMAP:
		if (0 == buf->baddr) {
			dprintk(1,"qbuf: mmap requested but buffer addr is zero!\n");
			goto done;
		}
		break;
	case V4L2_MEMORY_USERPTR:
		if (b->length < buf->bsize) {
			dprintk(1,"qbuf: buffer length is not enough\n");
			goto done;
		}
		if (STATE_NEEDS_INIT != buf->state && buf->baddr != b->m.userptr)
			q->ops->buf_release(q,buf);
		buf->baddr = b->m.userptr;
		break;
	case V4L2_MEMORY_OVERLAY:
		buf->boff = b->m.offset;
		break;
	default:
		dprintk(1,"qbuf: wrong memory type\n");
		goto done;
	}

	dprintk(1,"qbuf: requesting next field\n");
	field = videobuf_next_field(q);
	retval = q->ops->buf_prepare(q,buf,field);
	if (0 != retval) {
		dprintk(1,"qbuf: buffer_prepare returned %d\n",retval);